Flotation concentrate spheroidizing method

Abstract

The invention belongs to the field of mineral processing, and discloses a flotation concentrate spheroidizing method which comprises the following steps: carrying out table grading separation treatment on ore pulp containing flotation concentrate to be treated in advance to obtain first spheroidized particles and non-spheroidized particles; the shaking table grading and sorting process comprises a first-stage particle size grading process and a second-stage spherical sorting process which are carried out by adopting a shaking table; carrying out ore grinding treatment on the non-spheroidized particles under a ceramic ball medium, and then carrying out table grading separation treatment to obtain second spheroidized particles and tailings; and the first spheroidized particles and the second spheroidized particles are combined, and spheroidized concentrate is obtained. According to the method, a table classification-separation synergistic mechanism and a closed-loop grinding process are innovatively combined, the problems of serious over-crushing and high energy consumption in a traditional spheroidizing method are solved, the yield of spherical particles of mineral such as barite and quartz is increased to 80% or above, the sphericity degree of spherical products is larger than or equal to 0.85, and the machining efficiency and quality consistency of the spherical particles are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of mineral processing, in particular to the field of spheroidization of ore concentrates. Background Art

[0002] Particle spheroidization, a key process in materials processing, aims to transform irregular particles into spherical shapes through physical or chemical means to improve fluidity, packing density, and surface properties. Currently, this technology is widely used in fields such as ceramics, metallurgy, and electronic packaging, but existing processes still face significant technical bottlenecks.

[0003] Mainstream spheroidization methods include mechanical grinding, high-speed airflow impact spheroidization, spray drying, and chemical vapor deposition. Among them, mechanical grinding methods (such as ball milling and vibration milling) are widely used due to their simple equipment and process, but they still have problems such as difficulty in controlling sphericity, the easy regeneration of edges and corners caused by conventional steel balls or grinding media grinding, and excessive particle breakage caused by high-energy impact. For flotation concentrates, their particles are relatively small, making spheroidization more difficult, and it is difficult to control the required spheroidization degree, which can easily lead to excessive grinding of particles, which in turn limits their application. For example, for barite flotation particles, the spheroidization of their particles can effectively reduce the wear of drill tools during drilling, but the finer particles will affect their viscosity and dispersibility, and cause the barite particles to be lost in the cracks of the well wall. Therefore, there is an urgent need to systematically optimize the mechanical grinding method (ball milling process) to improve the particle sphericity while controlling the product particle size, and to promptly screen out the spherical particles that meet the requirements from the ground product.

[0004] The main methods for screening spherical particles include dry screening and inclined plane separation. Dry screening is only suitable when there is a significant difference in the particle size between irregular and spherical powders. Inclined plane separation exploits the differences in force and motion characteristics between spherical and non-spherical particles on a rough inclined surface to achieve separation. Spherical particles roll down the inclined surface, while non-spherical particles remain stuck. For example, patents CN1872431A and CN109482501A describe spherical powder screening and separation devices, which enable mechanized and continuous screening of millimeter-scale and narrow-size spherical powders. However, flotation concentrates undergo grinding prior to separation and enrichment, and microscopic analysis reveals distinct spherical and non-spherical particles in the product. Furthermore, the particle size of flotation concentrates is typically less than 74 μm, with a wide size distribution. This makes separation between spherical and non-spherical particles difficult to achieve using existing equipment or manual labor. Furthermore, the surface of flotation concentrates often adsorbs beneficiation reagents, causing severe particle agglomeration and poor incline separation efficiency. Therefore, it is urgent to develop a more efficient method for separating spherical particles from non-spherical particles based on the properties of flotation concentrate particles.

[0005] In summary, due to the characteristics of flotation concentrate, such as fine particle size, wide particle size range, easy agglomeration and over-grinding, it is urgent to develop new methods for separating spherical and irregular particles and optimize the parameters of the mechanical grinding process. Summary of the Invention

[0006] In view of the problems existing in the prior art, the present invention aims to provide a flotation concentrate spheroidization method, aiming to improve the spheroidization degree and uniformity of the concentrate, and reduce costs and increase efficiency.

[0007] The flotation concentrate has a fine particle size and a wide particle size distribution, and the particle size is basically less than 74μm. When the spheroidization operation is performed by mechanical grinding, the particles will be over-ground, and the existing spherical particles in the flotation concentrate are easily broken into irregular particles, resulting in low efficiency of the spheroidization process. Therefore, it is necessary to screen out the original / new qualified spherical particles in the flotation concentrate before mechanical grinding. The inclined separation method has a poor screening effect on micron-sized spherical particles, and the flotation concentrate is easy to agglomerate, further reducing the screening effect of spherical particles and irregular particles. In response to the problems faced by the spheroidization of flotation concentrate, the present invention provides the following solutions:

[0008] The flotation concentrate spheroidization method comprises pre-processing the pulp containing the flotation concentrate to be processed and the dispersant on a shaking table to obtain first spheroidized particles and non-spheroidized particles; the shaking table classification and sorting includes a first stage particle size classification and a second stage spheroidization sorting process using a shaking table;

[0009] The non-spheroidized particles are ground under ceramic ball media, and then subjected to shaking table classification and sorting to obtain second spheroidized particles and tailings;

[0010] The first spheroidized particles and the second spheroidized particles are combined to obtain a spheroidized concentrate.

[0011] In order to address the problems that flotation concentrate has low particle size, is difficult to spheroidize, and is prone to over-crushing during the spheroidization process, which in turn affects its application, the present invention innovatively compounds the concentrate and dispersant, and pre-grades and sorts the concentrate-dispersant mixed slurry based on a shaking table method, and then uses a ceramic medium for grinding treatment. This can achieve synergy, significantly improve the sphericity and uniformity of the concentrate, and help significantly reduce energy consumption.

[0012] In the present invention, the flotation concentrate to be processed includes at least one of barite, quartz and fluorite.

[0013] In the present invention, the solid concentration in the slurry is 15% to 25%;

[0014] The present invention shows that the dispersant can be used in conjunction with the subsequent shaking table classification and sorting treatment-grinding treatment to achieve synergy, enhance the spheroidization effect, and help improve the recovery rate of spheroidized particles.

[0015] In the present invention, the dispersant can be sodium hexametaphosphate, polyacrylamide, water glass, gul gum, etc.

[0016] In the present invention, the amount of the dispersant used is 0.2% to 0.4% of the mass of the concentrate to be processed, preferably 0.3% to 0.4%.

[0017] In the present invention, a grading-sorting process is carried out using a series of shaking table equipment, wherein the grading process is to achieve grading by utilizing the difference in particle size. Fine-grained particles float on the water surface and flow into the bottom of the shaking table under the action of gravity and downward water flow, while coarse particles tend to sink to the bottom of the water and flow to one side of the shaking table under the influence of the lateral force of the shaking table. The sorting is achieved by utilizing the characteristics of the particle morphology, for example, the difference in shaking table motion behavior between spherical particles and non-spherical particles. Spherical particles tend to roll downward on the surface of the shaking table and flow to the bottom under the action of water flow and gravity, while irregular particles are more difficult to roll and deposit in the transverse grooves, and flow to one side of the shaking table under the action of the lateral force. In the present invention, the grading and sorting process based on the shaking table helps to avoid the problem of particle pulverization in the subsequent grinding stage. In addition, it is also beneficial to improve the degree of spheroidization and particle uniformity, and it is also beneficial to reduce processing energy consumption.

[0018] The present invention performs classification and sorting on flotation concentrates such as barite concentrate or quartz concentrate. Unlike conventional gravity sorting, the concentrate grade is generally over 95%, the density of the particles in the concentrate is close, and the particles are easy to agglomerate. Therefore, during the first shaking table (i.e., particle size classification), barite of -20 μm is easily lifted by the water flow and enters the bottom of the shaking table under the action of gravity and downward water flow force; while concentrates with a particle size of 20 to 74 μm are more difficult to be lifted by the water flow, deposited in the transverse strip grooves, and flow to one side of the shaking table under the action of the transverse force, thereby achieving particle size classification. In addition, for concentrate particles of -20 μm or 20 to 70 μm, when the second shaking table (spherical sorting) is performed, the spherical particles roll downward on the surface of the shaking table under the action of water flow force and gravity; irregular particles are more difficult to roll and deposited in the transverse strip grooves, and flow to one side of the shaking table under the action of the transverse force, thereby achieving separation of spherical and irregular particles.

[0019] In the present invention, the first-stage particle size classification obtains particle size classification concentrates with particle sizes of 20 to 74 μm and -20 μm, and then the particle size classification concentrate is subjected to a second-stage spherical classification process to classify spherical particles therein.

[0020] In the present invention, during the first-stage particle size classification process, the shaking table has a flushing frequency of 290 to 340 times / min; a water flow velocity of 0.8 to 1.2 m / s; a bed stripe spacing of 2 to 6 mm, preferably 3 to 4 mm; a bed height of 0.5 to 3 mm, preferably 0.5 to 1.5 mm; and a shaking table sorting inclination angle of 2 to 3°, preferably 2.5 to 3.0°.

[0021] Under the optimal shaking table classification conditions, combined with other processes, better spheroidization effect and yield can be obtained.

[0022] Preferably, during the second-stage spherical sorting process, the shaking table has a flushing frequency of 280 to 330 times / min; the water flow rate is 0.4 to 0.6 m / s; the bed stripe spacing of the shaking table is 3 to 4 mm; the bed height of the shaking table is 1 to 3 mm, preferably 1 to 1.5 mm; and the shaking table sorting inclination angle is 2 to 3°, preferably 2.5 to 3.0°.

[0023] Under the optimal shaking table sorting conditions, combined with other processes, better spheroidization effect and yield can be obtained.

[0024] In the present invention, the shaking table pre-grading and sorting process and the grinding process are coupled, and further coordinated with the joint control of the grinding medium material, so that synergy can be achieved, the spheroidization degree and uniformity can be improved, and the particle size pulverization problem during the spheroidization process can be reduced.

[0025] In the present invention, the grinding process is stage grinding, including a first grinding process and a second grinding process, wherein the diameter of the ceramic ball medium in the first grinding process is 5 to 8 mm; the diameter of the ceramic ball medium in the second grinding process is 3 to 5 mm.

[0026] In the present invention, the staged grinding steps include: subjecting the non-spheroidized particles to a first-stage grinding process, subjecting the first-stage grinding material to the shaking table classification and sorting process to separate the spheroidized particles from the first-stage grinding material, and subjecting the non-spheroidized particles therein to a subsequent second-stage grinding process. Subsequently, subjecting the second-stage grinding material to the shaking table classification and sorting process to separate the spheroidized particles from the second-stage grinding material, and discarding the non-spheroidized particles therein. The spheroidized particles from the first-stage grinding material and the spheroidized particles from the second-stage grinding material are combined to form the second spheroidized particles.

[0027] In the present invention, the filling rate of the first grinding process is 15-18%, the rotation speed is 65-70% of the critical speed, and the grinding time is 10-15 minutes;

[0028] In the present invention, the filling rate of the second grinding process is 12-15%, the rotation speed is 55-60% of the critical speed, and the grinding time is 5-8 minutes.

[0029] In the present invention, the irregular particles obtained through the two-stage grinding and classification fractal process are discarded as tailings.

[0030] In the present invention, the sphericity of the concentrate after spheroidization is greater than 0.85.

[0031] Beneficial effects

[0032] The present invention uses a shaking table device to achieve efficient separation of spherical and irregular particles through a synergistic mechanism of classification and sorting. By optimizing the grinding media and parameters for irregular particles, most irregular particles are converted into spherical particles. This is specifically reflected in the following core advantages:

[0033] 1. High efficiency in spherical particle separation. Dispersants are used to achieve uniform distribution of fine, easily agglomerated flotation particles in the slurry. By taking advantage of the differences in the motion states of particles of different sizes and shapes on the shaking table surface, micron-level flotation particles can be graded and separated by shape. Spherical particles with a sphericity of ≥0.85 can be separated, reducing the processing capacity of the first and second stages of grinding by more than 50%, while preventing spherical particles from being ground into irregular particles.

[0034] 2. Optimizing the grinding process yields excellent results in producing spherical particles. Low-damage ceramic ball media and grinding parameters are selected to efficiently grind irregular particles into spherical particles. The newly generated spherical particles have a sphericity ≥ 0.85, a loss rate of irregular particles ≤ 20%, and an overall yield of spherical particles ≥ 80%.

[0035] 3. Wide particle size application range, low pollution in the process, and coarse spherical product particle size. The process can process micron-sized mineral flotation particles (such as quartz, barite, fluorite, etc.). The particle size distribution of flotation particles is wide, ranging from 0 to 74 μm. The particle size of spherical particles is coarse, D 50 ≥10μm, suitable for spheroidizing high-hardness minerals (Mohs hardness ≥7) such as quartz. Using ceramic media and chemical-free spheroidizing agent technology avoids heavy metal pollution and is environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 :Process flow chart;

[0037] Figure 2 : Particle size analysis results of the final spherical product in Example 1 (D 50 =17 μm);

[0038] Figure 3 : Microscope image of the final spherical product in Example 1;

[0039] Figure 4 : Normal distribution diagram and results of the sphericity of the final spherical product in Example 1. DETAILED DESCRIPTION

[0040] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention is further described in detail below with reference to specific embodiments and accompanying drawings.

[0041] The flotation concentrate spheroidization method of the present invention has the following optional steps:

[0042] a. Raw material pretreatment: Prepare the mineral concentrate into a slurry of a certain concentration and add a dispersant.

[0043] b. Shaking table grading and sorting: A double-layer shaking table is used in series. The first layer is graded by particle size, and the second layer is used to sort the shapes of each grade. The proportion of spherical particles in the concentrate / middlings is increased to more than 60%, and the sphericity of the product is measured using an image analyzer.

[0044] c. Stage grinding: First, in the first stage of grinding, a Φ500mm ceramic ball mill is used for the tailings, and zirconia ceramic balls with a diameter of 5-8mm are loaded, with a filling rate of 15-18%, a rotation speed of 65-70% of the critical speed, and a grinding time of 10-15 minutes. Then, the ground products are graded and sorted on a shaking table, and the concentrate (sphericity>0.85) is used as the finished product. The tailings enter the second stage of grinding; in the second stage of grinding, ceramic balls with a diameter of 3-5mm are used, with a filling rate of 12-15%, the rotation speed is reduced to 55-60% of the critical speed, and the grinding time is 5-8 minutes. After the second stage grinding products are graded and sorted on a shaking table, the substandard particles (sphericity<0.7) are discharged as tailings.

[0045] For the raw material pretreatment stage, the slurry concentration is 15% to 25%, preferably 20%.

[0046] Dispersants need to be added to the slurry, mainly sodium hexametaphosphate or sodium polyacrylate. Sodium hexametaphosphate is mainly used for the spheroidization of silicate minerals, and sodium polyacrylate is mainly used for alkaline earth metal minerals such as barite and fluorite.

[0047] The amount of dispersant used is 0.2% to 0.4%, preferably 0.3% to 0.4%.

[0048] During the shaker classification and enrichment stage, the shaker stroke rate is 290-340 strokes / min, preferably 310-330 strokes / min. The water flow rate during the shaker classification process is 0.8-1.2 m / s, preferably 0.9-1.0 m / s. The bed rib spacing is 2-6 mm, preferably 3-4 mm. The shaker inclination angle is 2-3°, preferably 2.5-3.0°.

[0049] Shaking table sorting stage: the shaking table has a stroke frequency of 280 to 330 times / min; the water flow rate is 0.4 to 0.6 m / s; the stripe spacing of the shaking table is 3 to 4 mm; the bed height of the shaking table is 1 to 3 mm, preferably 1 to 1.5 mm; the shaking table sorting inclination is 2 to 3°, preferably 2.5 to 3.0°.

[0050] For the first grinding stage, the diameter of the ceramic balls is 4 to 7 mm, preferably 5 to 6 mm.

[0051] The medium filling rate is 16-18%, preferably 17%.

[0052] The mill speed is 65-70% of the critical speed, preferably 66-68%.

[0053] The grinding time is 12 to 14 minutes, preferably 13 minutes.

[0054] For the secondary grinding stage, the diameter of the ceramic balls is 3-5 mm, preferably 4 mm.

[0055] The medium filling rate is 13-15%, preferably 14%.

[0056] The mill speed is 55-60% of the critical speed, preferably 56-58%.

[0057] The grinding time is 6 to 7 minutes, preferably 6.5 minutes.

[0058] The sphericity test method is an image statistics method. The main steps are: using microscopic measurement methods such as scanning electron microscopy or microscopes to obtain images of spherical and irregular particles, and then processing them with specialized particle image analysis software such as imageJ to obtain the sphericity information of each particle. The sphericity information of each particle is then statistically analyzed to obtain a normal distribution of sphericity. The median value of the normal distribution is the sphericity value of the spherical / irregular particles.

[0059] In the present invention, the concentrate is obtained by conventional flotation, for example, by collecting with a conventional fatty acid collector.

[0060] The shaking table equipment can be a well-known equipment in the industry that can be used for grading and sorting. For example, in a laboratory scenario, a laboratory mineral processing mud groove shaking table can be used.

[0061] Example 1: Preparation of barite spherical particles

[0062] A barite concentrate from Guizhou was selected to carry out particle spheroidization experiments. The barite concentrate was -74μm particles. The D 50 =37μm, the BaSO4 content in the concentrate is 95%, and the initial sphericity of the barite flotation concentrate is 0.62.

[0063] ①. Slurry adjustment process: Mix the barite flotation concentrate with water to adjust the pulp concentration to 18%, add polyacrylamide as a dispersant to the pulp, and the amount of dispersant is 0.25% of the mass of the barite flotation concentrate.

[0064] ② Particle Size Classification Process: The shaker's stroke rate was adjusted to 310 strokes / min, the flushing water flow rate to 1.0 m / s, the bed stripe spacing to 4 mm, the bed stripe height to 1.5 mm, the shaker sorting angle to 3.0°, and the feed rate to 0.02 t / h. After shaker processing, the barite flotation concentrate was classified into coarse and fine fractions. Of the coarse fraction, 20-74 μm particles accounted for 95%, and of the fine fraction, -20 μm particles accounted for 97%. The coarse and fine fractions were then subjected to two-stage shaker sorting, or spherical sorting.

[0065] ③. Spherical separation process: The shaker's stroke rate was adjusted to 300 strokes / min, the flushing water flow rate to 0.4m / s, the bed stripe spacing to 3mm, the bed stripe height to 1.5mm, the shaker separation angle to 3.0°, and the feed rate to 0.02t / h. After treatment on the shaker, the barite particles were classified into coarse spherical particles, fine spherical particles, coarse irregular particles, and fine irregular particles. The coarse and fine spherical particles were mixed to obtain spherical particles with a high sphericity of 0.89 and a yield of 68%. The coarse and fine irregular particles were mixed and then fed into the first grinding stage.

[0066] ④. Primary Grinding: Irregular particles (including coarse and fine particles) are added to the mill and ground using ceramic balls. The balls have a diameter of 6 mm, the mill filling rate is set to 17%, the mill speed is set to 68% of the critical speed, and the grinding time is set to 14 minutes. The primary grinding product is then sorted by size and sphericity according to the procedures and parameters of steps ② and ③. The primary grinding product is divided into spherical and irregular particles. The sphericity of the spherical particles is 0.90, and the yield is 18%. The irregular particles enter the secondary grinding stage.

[0067] ⑤. Secondary Grinding: The irregular particles from the previous stage are added to the mill and ground using ceramic balls. The balls have a diameter of 4 mm, the mill filling rate is set to 14%, the mill speed is 58% of the critical speed, and the grinding time is set to 7 minutes. The secondary milled product is then sorted by particle size and sphericity according to the procedures and parameters of steps ② and ③. The secondary milled product is divided into spherical and irregular particles. The sphericity of the spherical particles is 0.85, with a yield of 10%. The sphericity of the irregular particles is 0.45, with a yield of 4%. The irregular particles are discharged as tailings.

[0068] The spherical particles obtained in steps ③, ④ and ⑤ are mixed to form the final spherical product. 50 =17 μm, the sphericity of the spherical product is 0.89, and the total yield is 96%.

[0069] Example 2: Preparation of quartz spherical particles

[0070] A quartz concentrate from Inner Mongolia was selected to conduct particle spheroidization experiments. The quartz concentrate was -74μm particles. The D 50 =25μm, the SiO2 content in the concentrate is 99.5%, and the initial sphericity of the quartz flotation concentrate is 0.58.

[0071] ①. Slurry adjustment process: The quartz flotation concentrate is mixed with water to adjust the pulp concentration to 22%, and sodium hexametaphosphate is added to the pulp as a dispersant. The amount of dispersant is 0.35% of the mass of the quartz flotation concentrate.

[0072] ② Particle Size Classification Process: The shaker's stroke rate was adjusted to 340 strokes / min, the flushing water flow rate to 0.8 m / s, the bed stripe spacing to 2 mm, the bed stripe height to 0.5 mm, the shaker sorting angle to 3.0°, and the feed rate to 0.02 t / h. After shaker processing, the quartz flotation concentrate was classified into coarse and fine fractions. Of the coarse fraction, 20-74 μm particles accounted for 93%, while of the fine fraction, -20 μm particles accounted for 95%. The coarse and fine fractions were then subjected to two-stage shaker sorting, or spherical sorting.

[0073] ③. Spherical separation process: The shaker's stroke rate was adjusted to 310 strokes / min, the flushing water flow rate to 0.4 m / s, the bed stripe spacing to 4 mm, the bed stripe height to 1.0 mm, the shaker's separation angle to 2.5°, and the feed rate to 0.02 t / h. After the shaker treatment, the quartz particles were classified into coarse spherical particles, fine spherical particles, coarse irregular particles, and fine irregular particles. The coarse and fine spherical particles were mixed to obtain spherical particles with a high sphericity of 0.86 and a yield of 54%. The coarse and fine irregular particles were then mixed and fed into the primary grinding stage.

[0074] ④. Primary Grinding: Irregular particles (including coarse and fine particles) are added to the mill and ground using ceramic balls. The balls have a diameter of 5 mm, the mill filling ratio is set to 16%, the mill speed is set to 66% of the critical speed, and the grinding time is set to 12 minutes. The primary grinding product is then sorted by particle size and sphericity according to the procedures and parameters of steps ② and ③. The primary grinding product is divided into spherical and irregular particles. The sphericity of the spherical particles is 0.85, and the yield is 25%. The irregular particles enter the secondary grinding stage.

[0075] ⑤. Secondary Grinding: The irregular particles from the previous stage are added to the mill and ground using ceramic balls. The balls have a diameter of 3 mm, the mill filling rate is set to 13%, the mill speed is 56% of the critical speed, and the grinding time is set to 6 minutes. The secondary milled product is then sorted by size and sphericity according to the procedures and parameters of steps ② and ③. The secondary milled product is divided into spherical and irregular particles. The sphericity of the spherical particles is 0.83, with a yield of 9%. The sphericity of the irregular particles is 0.42, with a yield of 12%. The irregular particles are discharged as tailings.

[0076] The spherical particles obtained in steps ③, ④ and ⑤ are mixed to form the final spherical product. 50 =16 μm, the sphericity of the spherical product is 0.85, and the total yield is 88%.

[0077] Example 3: Preparation of fluorite spherical particles

[0078] A fluorite concentrate from Hunan was selected to carry out the particle spheroidization experiment. The fluorite concentrate was -74μm particles. The D 50 =50μm, the CaF2 content in the concentrate is 90%, and the initial sphericity of the fluorite flotation concentrate is 0.65.

[0079] ①. Slurry adjustment process: Mix the fluorite flotation concentrate with water to adjust the pulp concentration to 25%, add sodium hexametaphosphate as a dispersant to the pulp, and the amount of dispersant is 0.30% of the mass of the fluorite flotation concentrate.

[0080] ② Particle Size Classification Process: The shaker's stroke rate was adjusted to 290 strokes / min, the flushing water flow rate to 1.1 m / s, the bed stripe spacing to 6 mm, the bed stripe height to 1.5 mm, the shaker sorting angle to 3.0°, and the feed rate to 0.02 t / h. After shaker processing, the fluorite flotation concentrate was classified into coarse and fine fractions. Of the coarse fraction, 98% were particles of 20-74 μm, while 98% were particles of -20 μm. The coarse and fine fractions were then subjected to two-stage shaker sorting, or spherical sorting.

[0081] ③. Spherical Sorting Process: The shaker's stroke rate was adjusted to 280 strokes / min, the flushing water flow rate to 0.6 m / s, the bed stripe spacing to 4 mm, the bed stripe height to 1.5 mm, the shaker's sorting angle to 2.5°, and the feed rate to 0.02 t / h. After treatment on the shaker, the fluorite particles were classified into coarse spherical particles, fine spherical particles, coarse irregular particles, and fine irregular particles. The coarse and fine spherical particles were mixed to produce spherical particles with a high sphericity of 0.91 and a yield of 61%. The coarse and fine irregular particles were then mixed and fed into the primary grinding process.

[0082] ④. Primary Grinding: Irregular particles (including coarse and fine particles) are added to the mill and ground using ceramic balls. The balls have a diameter of 7 mm, the mill filling ratio is set to 18%, the mill speed is set to 70% of the critical speed, and the grinding time is set to 15 minutes. The primary grinding product is then sorted by particle size and sphericity according to the procedures and parameters of steps ② and ③. The primary grinding product is divided into spherical and irregular particles. The sphericity of the spherical particles is 0.90, with a yield of 23%. The irregular particles enter the secondary grinding stage.

[0083] ⑤. Secondary Grinding: The irregular particles from the previous stage are added to the mill and ground using ceramic balls. The balls have a diameter of 5 mm, the mill filling rate is set to 15%, the mill speed is set to 60% of the critical speed, and the grinding time is set to 8 minutes. The secondary milled product is then sorted by particle size and sphericity according to the procedures and parameters of steps ② and ③. The secondary milled product is divided into spherical and irregular particles. The sphericity of the spherical particles is 0.85, with a yield of 7%. The sphericity of the irregular particles is 0.50, with a yield of 9%. The irregular particles are discharged as tailings.

[0084] The spherical particles obtained in steps ③, ④ and ⑤ are mixed to form the final spherical product. 50 =33 μm, the sphericity of the spherical product is 0.90, and the total yield is 91%.

[0085] Example 4: Preparation of barite spherical particles

[0086] The barite raw material and operating parameters selected in Example 5 were the same as those in Example 1. Only the following parameters (parameters in Table 1) were changed during the spheroidization process to make single factor adjustments. The results are shown in Table 1.

[0087] a: No dispersant is added in step ①;

[0088] b: The flushing water flow rate in step ② and step ③ is changed to 0.8m / s and 0.6m / s;

[0089] c: The height of the bed strips in steps ② and ③ is controlled to be 3mm;

[0090] d: The inclination angle of the shaking table in steps ② and ③ is controlled to 2°;

[0091] e: The diameters of the ceramic balls in step ④ and step ⑤ were changed to 8mm and 5mm respectively;

[0092] f: The ceramic ball filling rates in step ④ and step ⑤ are changed to 15% and 12% respectively;

[0093] g: The mill speeds in step ④ and step ⑤ are 65% and 55% of the critical speed, respectively;

[0094] h: The grinding time of step ④ and step ⑤ is 10 min and 8 min respectively.

[0095] Table 1 Effect of main parameters of spheroidization process on sphericity and yield of final product (%)

[0096]

[0097] It can be seen from Table 1 that under the classification, sorting and grinding parameters described in the present invention, a spheroidization effect higher than 0.85 can be obtained, and under preferred conditions such as preferred bed height and inclination angle, the spheroidization degree and yield are even better.

[0098] Example 5: Preparation of barite spherical particles

[0099] The barite raw material and operating parameters used in Example 5 were the same as those in Example 1, except that the milled product from the first-stage grinding in step 4 was not subjected to classification and sorting, and was directly processed to step 5, where the second-stage grinding product was subjected to classification and sorting. The sphericity of the spherical particles obtained in step 5 was 0.78, with a yield of 11%. The sphericity of the irregular particles was 0.59, with a yield of 21%.

[0100] The spherical particles obtained in steps ③ and ⑤ are mixed to form the final spherical product. 50 =10 μm, the sphericity of the spherical product is 0.85, and the total yield is 79%.

[0101] Comparative Example 1

[0102] Compared with Example 1, the only difference is that the particle size classification process in step ② is not performed. Similarly, the particle size classification process in steps ④ and ⑤ is also not performed. Other operations and parameters are the same as in Example 1.

[0103] The final spherical product D 50 =8μm, the sphericity of the spherical product is 0.75, and the total yield is 56%.

[0104] Comparative Example 2

[0105] Compared with Example 1, the only difference is that steps ② and ③ are not performed. Similarly, in steps ④ and ⑤, the particle size classification process ② and the particle shape sorting process ③ are not performed. That is, the flotation concentrate is subjected to the first and second stage grinding and the sphericity of the ground product is measured. Other operations and parameters are the same as in Example 1.

[0106] The final spherical product D 50 =7 μm, the sphericity of the spherical product is 0.63, and the total yield is 100%.

[0107] Comparative Example 3

[0108] Compared with Example 1, the only difference is that step ③ particle shape sorting treatment is not performed. Similarly, step ③ particle shape sorting treatment is also not performed. Other operations and parameters are the same as in Example 1.

[0109] The final spherical product D 50 =9 μm, the sphericity of the spherical product is 0.76, and the total yield is 57%.

[0110] Comparative Example 4

[0111] The barite raw material and operating parameters used in Comparative Example 4 are the same as those in Example 1, except that in the spheroidization experiment, step ② particle size classification and step ③ particle shape separation are performed using a chute. 50 =8μm, the sphericity of the spherical product is 0.67, and the total yield is 75%.

[0112] Comparative Example 5

[0113] The barite raw material and operating parameters used in Comparative Example 5 are the same as those in Example 1, except that in the spheroidization experiment, step ② of the particle size classification in Comparative Example 5 is carried out by a hydrocyclone. 50 =15μm, the sphericity of the spherical product is 0.83, and the total yield is 86%.

[0114] Comparative Example 6

[0115] The barite raw material and operating parameters used in Comparative Example 6 are the same as those in Example 1, except that steel balls are used instead of ceramic balls during the spheroidization experiment. The diameter of the steel balls used in the first stage of grinding is 6 mm, and the diameter of the steel balls used in the second stage of grinding is 4 mm. 50 =6μm, the sphericity of the spherical product is 0.76, and the total yield is 64%.

[0116] Comparative Example 7

[0117] The barite raw material and operating parameters used in Comparative Example 7 are the same as those in Example 1, except that steel segments are used instead of ceramic balls during the spheroidization experiment. The steel segments used in the first stage of grinding have a diameter of 6 mm and a height of 7.5 mm, and the steel balls used in the second stage of grinding have a diameter of 4 mm and a height of 6.0 mm. 50 =5μm, the sphericity of the spherical product is 0.77, and the total yield is 69%.

[0118] Comparative Example 8

[0119] The barite raw material and operating parameters used in Comparative Example 8 are the same as those in Example 1, except that no flushing water is added during the spheroidization experiment. 50=7μm, the sphericity of the spherical product is 0.62, and the total yield is 57%.

[0120] By comparing Examples 1 to 3, it can be seen that for the flotation concentrate particle spheroidization experiment, by controlling the shaking table and mill parameters in the process within an appropriate range, spherical products with a sphericity greater than 0.85 and a yield greater than 85% can be obtained, and the overall particle size of the spherical products is relatively coarse.

[0121] By comparing Example 1 and Example 4, it can be seen that the addition of a dispersant is particularly important for the sphericity experiment. After changing the process parameters, spherical products with a sphericity > 0.85 can still be obtained, but the product yield and particle size will vary.

[0122] By comparing Example 1 and Example 5, it can be seen that better indicators can be obtained by performing stage grinding, stage particle size classification and stage particle shape sorting.

[0123] By comparing Example 1 with Comparative Examples 1 to 3, it can be seen that the sphericity of the spherical products obtained in single step ② or step ③ is lower than 0.85, and the sphericity of the spherical products obtained without step ② and step ③ is lower than 0.7.

[0124] Comparison of Example 1 with Comparative Examples 4-8 shows that using a hydrocyclone or chute instead of a shaker, or using steel balls or steel segments instead of ceramic balls for sphericity testing, the resulting spherical products have a sphericity below 0.85. Furthermore, compared to a dry shaker, a wet shaker with flushing water provides superior results.

[0125] The above embodiments are intended only to illustrate the technical solutions of the present invention and are not intended to limit the present invention. It should be noted that the above preferred embodiments should not be considered as limiting the present invention, and the scope of protection of the present invention should be based on the scope defined in the claims. It will be apparent to those skilled in the art that various improvements and modifications can be made without departing from the spirit and scope of the present invention, and such improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A flotation concentrate spheroidization method, characterized in that: The slurry containing the flotation concentrate to be processed and the dispersant is pre-processed by a shaking table classification and sorting process to obtain first spheroidized particles and non-spheroidized particles; the shaking table classification and sorting includes a first stage particle size classification and a second stage spherical sorting process using a shaking table; The non-spheroidized particles are ground under ceramic ball media, and then subjected to shaking table classification and sorting to obtain second spheroidized particles and tailings; The first spheroidized particles and the second spheroidized particles are combined to obtain a spheroidized concentrate.

2. The flotation concentrate spheroidization method according to claim 1, characterized in that: The flotation concentrate to be processed includes at least one of barite, quartz and fluorite.

3. The flotation concentrate spheroidization method according to claim 1, characterized in that: The solid concentration in the slurry is 15% to 25%; Preferably, the amount of dispersant used is 0.2% to 0.4% of the mass of the concentrate to be processed, preferably 0.3% to 0.4%.

4. The flotation concentrate spheroidization method according to claim 1, characterized in that: The first-stage particle size classification obtains particle size classification concentrates with particle sizes ranging from 20 to 74 μm and -20 μm, and then the particle size classification concentrates are subjected to a second-stage spherical classification process to select spherical particles therein.

5. The flotation concentrate spheroidization method according to claim 1 or 4, characterized in that: During the first-stage particle size classification process, the shaking table has a stroke frequency of 290 to 340 times / min; the water flow rate is 0.8 to 1.2 m / s; the bed stripe spacing of the shaking table is 2 to 6 mm, preferably 3 to 4 mm; the bed height of the shaking table is 0.5 to 3 mm, preferably 0.5 to 1.5 mm; the shaking table sorting inclination angle is 2 to 3 degrees, preferably 2.5 to 3.0 degrees; Preferably, during the second-stage spherical sorting process, the shaking table has a flushing frequency of 280 to 330 times / min; the water flow rate is 0.4 to 0.6 m / s; the bed stripe spacing of the shaking table is 3 to 4 mm; the bed height of the shaking table is 1 to 3 mm, preferably 1 to 1.5 mm; and the shaking table sorting inclination angle is 2 to 3°, preferably 2.5 to 3.0°.

6. The method for spheroidizing flotation concentrate according to claim 1, wherein: The grinding process is stage grinding, including the first grinding process and the second grinding process. The diameter of the ceramic ball medium in the first grinding process is 5 to 8 mm; the diameter of the ceramic ball medium in the second grinding process is 3 to 5 mm. Preferably, the stage grinding step is: subjecting the non-spheroidized particles to a first-stage grinding treatment, subjecting the first-stage grinding material to the shaking table classification and sorting treatment, separating the spheroidized particles in the first-stage grinding material, and subjecting the non-spheroidized particles therein to a subsequent second-stage grinding treatment, and then subjecting the second-stage grinding material to the shaking table classification and sorting treatment, separating the spheroidized particles in the second-stage grinding material, and discarding the non-spheroidized particles therein.

7. The method for spheroidizing flotation concentrate according to claim 6, wherein: The filling rate of the first grinding process is 15-18%, the rotation speed is 65-70% of the critical speed, and the grinding time is 10-15 minutes.

8. The method for spheroidizing flotation concentrate according to claim 6, wherein: The filling rate of the second grinding process is 12-15%, the rotation speed is 55-60% of the critical speed, and the grinding time is 5-8 minutes.

9. The flotation concentrate spheroidization method according to claim 1, characterized in that: The irregular particles obtained through the secondary grinding and classification fractal process are discarded as tailings.

10. The method for spheroidizing flotation concentrate according to claim 1, wherein: The sphericity of the concentrate after spheroidization is >0.85.

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